Telephone-receiver.



B. D. WILLIS.

TELEPHONE RECEIVER. APPLICATION FILED OCT.28.1908.

Patented Apr. 25, 1916.

I eras rnr BERNARD ID. IITIS, OF CHICAGO, ILLINOIS, ASSIGr'NOIt 'IU AUTOMATIE lEBllld'U'IlEtF CUIllIIPAIt'Y, 0F GHICAGU, ILLINOIS, A CORPORATION OF ILLIIQ'UIFe".

TELEPHONE-RECEIVER.

means.

Specification of Letters llatent.

Patented Apr, tare,

application filed October 5th, 1908. taerial Il'o. lti didd.

To all whom it may concern:

- Be it hown that I, BERNARD D. Winnrs, a citmen oi the United States of America, and resident of Ghicago, Cook county, Ill1- nois, have invented a certain new and useful Improvement in Telephone-Receivers, OI which the tollowin is a specification,

My invention re ates to telephone rece vers.that is to say, the instruments whlch are held to the ear to enable the listener to hear the voice or other vibrations transmitted from the other end of the ClI'CllllLr In the use of devices of this kind it has been the general practice to employ permanent magnets for polarizing the same, and to provide electromagnet coils in conjunction therewith tor influencing the diaphragm oi the re ceiver, With receivers of this character it has also been the general practice to exclude the coils of the receiver from the path of battery current-that is to say, to so arrange the. circuits that no battery current wlll flow through the coils which operate the diaa phragm. If battery currentwas permitted to pass through the said coils, provision has always been made for preventing such flow oi current from-energizing the magnet, and, furthermore, any flow of battery current in the diaphragm coils has always been in combination with a permanent magnet, at least so tar as I am now aware. In the actual operation out telephoneexchanges the loregoing has, therefore, been the general practice. t

The object of my invention is, therefore,

the provision of a commercially useful and highly efiicient telephone receiver in which there is no permanent magnet, and 1n whlch the coils for operating the diaphragm are connected directly in series with the transmitter, thus', utilizing the flow of battery current for attracting the diaphragm oi the receiver and insuring as good results, from a practical and commercial standpoint, as would ordinarily be obtained by the use out a receiver having a permanent magnet.

It is also an object to provide certain de tails and features o'lr' improvement tending to increase the generaler'hciency and serviceof a telephone receiverot-this partic Y To the reregoing and other useiul ends,

hereinafter ment of the electromagnet and poles thereof relative to the center oi the end of the receiver. Fig. 5 is a detail sectional view illustrating a modified form of the construction shown in Fig. 1. Fig. 6 is a diagram of a telephone circuit illustrating the manner in which my improved receiver may he connect-ed in the line in series with the transmit 'ter in a common battery system.

its thus illustrated, and referring more particularly to Figs. 1 to d, inclusive, it will be seen that my invention comprises a brass cup A having a flange or perimeter a; that forms a seat or marginal bearing for the diaphragm B, said cup being slightly flaring in form. The said flange a is adapted to engage the clrcular end edge of the receiver casing C, and the diaphragm and cup are clamped in place thereon by means of the usual apertured cap D, which latter is adapted to screw upon the open end portion of the said casing, both the casing and cap being preterably made ofrubber vulcanite. The said cup has its smaller end or bottom wall 0; provided with two aperturesarranged preterably at opposite sides of the center thereof and provided with insulating bushings a thus providing insulated apertures in the back or bottom of the cup. The electromagnet It has a cylindric core 6 upon which is mounted the winding or coil of the magnet, and to the bear end of which is secured the bottom oil a soft iron ,eup e, which cup forms a shelliorthe coil or winding of the magnet. The electrom'agnet thus formed is secured the back or bottom of the brass cup' 1%. by means of a screw e whi latter extends through a central. opening in the said brass cup, through a central opening in the soft iron cup e, and then into a threaded opening orisocket in the end of the core e, a small washer being preferably interposed between the backs or bottoms of the two- "cups. In this way the electromagnet is firmly clamped in place atthe center of the brass cupAand centrally of the diaphragm of the recei er. The cup e is preferably o'fo'rmed wit longitudinal slots e, which slots divide the cylindric, sides of the cup into .four' portions which are separated" at their outer ends but united at their other ends through the medium of the back or hot- '151tom ofthe' cupfi i'lt will be seen that the -'sem1-c1rc'1j1lar or segmental pole pieces e are" arranged concentrically in a circle around the oute'r'end of the core 6, and that consequently both poles of the electromagnet are in'juxtaposition to the back of the diaphragm, so that the magnetic circuit is closed through the latter when the magnetis energized by a flow of electrical current therein. Onepole ofthe magnet mat the exact center of the diaphragm, and the other pole of the magnet acts'on the diaphragm along the line of a circle extending concentrically around the-other pole, wh'ereby a ing i that affords access to the screw-e 40 whereby the electromagnet can be detached from the brass cup. Brass terminal pieces or binding posts 7 are inserted through the block F and provided With pro ectmg portions F that extend through-the bushings a and into the interiorof the-brass cup, where they are then suitably connected with the terminals of the ,coil or winding of the electromagnet. These binding posts f are provided with clamping screws f, and each post'is adapted to receive one of the eord terminals or plugs f that form the terminals of the flexible cord f extending rearwardly through the casing of the receiver, in the ordinary and well-known manner. The

said cord has a loop or attaching portion 7 that engages the hitching post f whereby the weight of the receiver is not sustained by the terminal portions F, but instead by a special or separate connectlon with the cord. r

Referrin to Fig. 6 it will be seen that the receivers g are here shown .diagrammat1- cally and-in series with the transmitters G in a common battery system. As shown, the

- $5 current from the central battery H is suppliedover the line circuit and passes to the transmitters and receivers at the substationsywhereby as soon as the line circuit is closed the diaphragms of the, receivers are placed under a stress or tensionas a result of. the energizing of the electromagnets of the said receivers. In this way no permanent magnets are necessary for the receivers, as both the battery and the voice-currents traverse the coils or windings-by which the "diaphragms of the receivers are actuated.

In Fig. 5 the construction is substantially the same as that shown in Fig. 1 except that the electromagnet and its cup are adjustably secured to a brass arm I, instead of to the bottom of the brasscup, said arm being integral with the brass ring 2' which forms a seat or marginal bearing for the dia- -Which are preferably equal in length. I find that this construction of cup gives the best results, although, obviously, for the broader purposes of my invention the magnet may have its rear end provided with a pole piece of any suitableform or character.

A receiver of the foregoing character has many advantages. As there is no permanent magnet the casing can be made smaller than heretofore, and can be shaped in various ways, depending upon the style. of telephone apparatus in connection with which it is to be used. Furthermore, it involves less metal and is consequently lighter than the old style of receiver, notwithstanding that. in actual practice it is found to be fully as eiiicient, atleast as far as the receiving qualities thereof are concerned.

What I claim as my invention is 1. A telephone receiver of the direct battery type having a diaphragm, a diaphragm support, a shell and cap to hold said support and diaphragm together, an insulating member removably mounted on the outside face of said support, connectors mounted upon said member, an electromagnet mounted and having its magnetic circuit wholly within said diaphragm support, means for holding said electromagnet in place, and an opening through said insulating member to receive said magnet holding means.

2. A telephone receiver of the direct battery type having a diaphragm, a diaphragm" support, a shell and cap to hold said support and diaphragm together, an insulating memnineteen lief i-emoveloly niountedon theoutsi'de face Signed by im at Uhicago, Cook county, of sand support, connectors mounted j'upon Illinois, this 24th day of October, 1908.

said member on electromaet mounted I with said diep hi-agm and support, endoeon- BERNARD L 5 tinuous section, of l'vhfilECGlVGl core project- Witnesses:

ing through said insulating member to hold J. N01131:,

said eleetromatgnet in place. 7 E. CLEGG. 

